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1 | /*- |
2 | * Copyright (c) 1990 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * Margo Seltzer. | |
7 | * | |
8 | * %sccs.include.redist.c% | |
9 | */ | |
10 | ||
11 | #if defined(LIBC_SCCS) && !defined(lint) | |
c6ad6315 | 12 | static char sccsid[] = "@(#)hash_page.c 5.11 (Berkeley) %G%"; |
6d1be33f KB |
13 | #endif /* LIBC_SCCS and not lint */ |
14 | ||
15 | /****************************************************************************** | |
16 | PACKAGE: hashing | |
17 | ||
18 | DESCRIPTION: | |
19 | Page manipulation for hashing package. | |
20 | ||
21 | ROUTINES: | |
22 | External | |
23 | __get_page | |
24 | __add_ovflpage | |
25 | Internal | |
26 | overflow_page | |
27 | open_temp | |
28 | ******************************************************************************/ | |
29 | ||
30 | #include <sys/param.h> | |
fb91cf55 | 31 | #include <fcntl.h> |
2c4a3a07 | 32 | #include <signal.h> |
6d1be33f KB |
33 | #include <assert.h> |
34 | #include <errno.h> | |
35 | #include <db.h> | |
36 | #include <stdio.h> | |
fb91cf55 KB |
37 | #include <stdlib.h> |
38 | #include <string.h> | |
867ff150 | 39 | #include <unistd.h> |
6d1be33f KB |
40 | #include "hash.h" |
41 | #include "page.h" | |
42 | ||
43 | /* Externals */ | |
44 | /* buf.c */ | |
45 | extern BUFHEAD *__get_buf(); | |
46 | extern void __reclaim_buf(); | |
47 | ||
48 | /* big.c */ | |
49 | extern int __big_split(); | |
50 | extern int __big_insert(); | |
51 | extern int __big_delete(); | |
52 | extern int __find_bigpair(); | |
53 | ||
54 | /* dynahash.c */ | |
55 | extern int __call_hash(); | |
56 | extern int __expand_table(); | |
57 | ||
58 | /* my externals */ | |
59 | extern int __get_page(); | |
60 | extern BUFHEAD *__add_ovflpage(); | |
61 | extern int __split_page(); | |
62 | extern int __addel(); | |
63 | ||
64 | /* my internals */ | |
65 | static u_short overflow_page(); | |
66 | static int open_temp(); | |
cd02bd08 | 67 | static int ugly_split(); |
6d1be33f KB |
68 | static void squeeze_key(); |
69 | static void putpair(); | |
70 | ||
71 | #ifdef HASH_STATISTICS | |
72 | extern long hash_accesses, hash_collisions, hash_expansions, hash_overflows; | |
73 | #endif | |
74 | #define PAGE_INIT(P) \ | |
75 | { \ | |
76 | ((u_short *)P)[0] = 0; \ | |
77 | ((u_short *)P)[1] = hashp->BSIZE - 3 * sizeof(u_short); \ | |
78 | ((u_short *)P)[2] = hashp->BSIZE; \ | |
79 | } | |
80 | ||
81 | /* | |
82 | This is called AFTER we have verified that there is room on the | |
83 | page for the pair (PAIRFITS has returned true) so we go right | |
84 | ahead and start moving stuff on. | |
85 | */ | |
86 | static void | |
87 | putpair(p, key, val) | |
88 | char *p; | |
89 | DBT *key; | |
90 | DBT *val; | |
91 | { | |
92 | register u_short n; | |
93 | register u_short off; | |
94 | register u_short *bp = (u_short *) p; | |
95 | ||
96 | /* enter the key first */ | |
97 | n = bp[0]; | |
98 | ||
99 | off = OFFSET(bp) - key->size; | |
100 | bcopy( key->data, p+off, key->size ); | |
101 | bp[++n] = off; | |
102 | ||
103 | /* now the data */ | |
104 | off -= val->size; | |
105 | bcopy(val->data, p + off, val->size); | |
106 | bp[++n] = off; | |
107 | ||
108 | /* adjust page info */ | |
109 | bp[0] = n; | |
110 | bp[n+1] = off - ((n+3)*sizeof(u_short)); | |
111 | bp[n+2] = off; | |
112 | return; | |
113 | } | |
114 | /* | |
115 | 0 OK | |
116 | -1 error | |
117 | */ | |
118 | extern int | |
119 | __delpair(bufp, ndx) | |
120 | BUFHEAD *bufp; | |
121 | register int ndx; | |
122 | { | |
123 | register u_short *bp = (u_short *) bufp->page; | |
124 | register int n = bp[0]; | |
125 | register u_short newoff; | |
126 | u_short pairlen; | |
127 | ||
128 | if ( bp[ndx+1] < REAL_KEY ) return ( __big_delete ( bufp, ndx ) ); | |
129 | if ( ndx != 1 ) newoff = bp[ndx-1]; | |
130 | else newoff = hashp->BSIZE; | |
131 | pairlen = newoff - bp[ndx+1]; | |
132 | ||
133 | if ( ndx != (n-1) ) { | |
134 | /* Hard Case -- need to shuffle keys */ | |
135 | register int i; | |
136 | register char *src = bufp->page + (int)OFFSET(bp); | |
137 | register char *dst = src + (int)pairlen; | |
138 | bcopy ( src, dst, bp[ndx+1] - OFFSET(bp) ); | |
139 | ||
140 | /* Now adjust the pointers */ | |
141 | for ( i = ndx+2; i <= n; i += 2 ) { | |
142 | if ( bp[i+1] == OVFLPAGE ) { | |
143 | bp[i-2] = bp[i]; | |
144 | bp[i-1] = bp[i+1]; | |
145 | } else { | |
146 | bp[i-2] = bp[i] + pairlen; | |
147 | bp[i-1] = bp[i+1] + pairlen; | |
148 | } | |
149 | } | |
150 | } | |
151 | ||
152 | /* Finally adjust the page data */ | |
153 | bp[n] = OFFSET(bp) + pairlen; | |
154 | bp[n-1] = bp[n+1] + pairlen + 2 * sizeof(u_short); | |
155 | bp[0] = n-2; | |
156 | hashp->NKEYS--; | |
157 | ||
158 | bufp->flags |= BUF_MOD; | |
159 | return (0); | |
160 | } | |
161 | /* | |
162 | -1 ==> Error | |
163 | 0 ==> OK | |
164 | */ | |
165 | extern int | |
166 | __split_page(obucket, nbucket) | |
167 | int obucket; | |
168 | int nbucket; | |
169 | { | |
170 | DBT key; | |
171 | DBT val; | |
172 | ||
173 | register BUFHEAD *new_bufp; | |
174 | register BUFHEAD *old_bufp; | |
175 | register u_short *ino; | |
176 | register char *np; | |
a51caf1c KB |
177 | int n; |
178 | int ndx; | |
179 | int retval; | |
6d1be33f KB |
180 | char *op; |
181 | ||
182 | u_short copyto = (u_short)hashp->BSIZE; | |
6d1be33f | 183 | u_short diff; |
a51caf1c | 184 | u_short off = (u_short)hashp->BSIZE; |
6d1be33f | 185 | u_short moved; |
6d1be33f KB |
186 | |
187 | old_bufp = __get_buf ( obucket, NULL, 0 ); | |
188 | new_bufp = __get_buf ( nbucket, NULL, 0 ); | |
189 | ||
a51caf1c KB |
190 | old_bufp->flags |= (BUF_MOD|BUF_PIN); |
191 | new_bufp->flags |= (BUF_MOD|BUF_PIN); | |
6d1be33f KB |
192 | |
193 | ino = (u_short *)(op = old_bufp->page); | |
194 | np = new_bufp->page; | |
195 | ||
196 | moved = 0; | |
197 | ||
198 | for (n = 1, ndx = 1; n < ino[0]; n+=2) { | |
199 | if ( ino[n+1] < REAL_KEY ) { | |
a51caf1c KB |
200 | retval = ugly_split( obucket, old_bufp, new_bufp, |
201 | copyto, moved ); | |
202 | old_bufp->flags &= ~BUF_PIN; | |
203 | new_bufp->flags &= ~BUF_PIN; | |
204 | return(retval); | |
205 | ||
6d1be33f | 206 | } |
c6ad6315 | 207 | key.data = (u_char *)op + ino[n]; |
6d1be33f KB |
208 | key.size = off - ino[n]; |
209 | ||
210 | if ( __call_hash ( key.data, key.size ) == obucket ) { | |
211 | /* Don't switch page */ | |
212 | diff = copyto - off; | |
213 | if ( diff ) { | |
214 | copyto = ino[n+1] + diff; | |
215 | bcopy ( op + ino[n+1], op + copyto, off-ino[n+1]); | |
216 | ino[ndx] = copyto + ino[n] - ino[n+1]; | |
217 | ino[ndx+1] = copyto; | |
218 | } else copyto = ino[n+1]; | |
219 | ndx += 2; | |
220 | } else { | |
221 | /* Switch page */ | |
c6ad6315 | 222 | val.data = (u_char *)op + ino[n+1]; |
6d1be33f KB |
223 | val.size = ino[n] - ino[n+1]; |
224 | putpair( np, &key, &val); | |
225 | moved +=2; | |
226 | } | |
227 | ||
228 | off = ino[n+1]; | |
229 | } | |
230 | ||
231 | /* Now clean up the page */ | |
232 | ino[0] -= moved; | |
233 | FREESPACE(ino) = copyto - sizeof(u_short) * (ino[0]+3); | |
234 | OFFSET(ino) = copyto; | |
235 | ||
236 | #ifdef DEBUG3 | |
237 | fprintf(stderr, "split %d/%d\n", | |
238 | ((u_short *) np)[0] / 2, | |
239 | ((u_short *) op)[0] / 2); | |
240 | #endif | |
a51caf1c KB |
241 | /* unpin both pages */ |
242 | old_bufp->flags &= ~BUF_PIN; | |
243 | new_bufp->flags &= ~BUF_PIN; | |
6d1be33f KB |
244 | return(0); |
245 | } | |
246 | /* | |
247 | 0 ==> success | |
248 | -1 ==> failure | |
249 | ||
a51caf1c KB |
250 | Called when we encounter an overflow or big key/data page during |
251 | split handling. | |
252 | This is special cased since we have to begin checking whether | |
6d1be33f KB |
253 | the key/data pairs fit on their respective pages and because |
254 | we may need overflow pages for both the old and new pages | |
a51caf1c KB |
255 | |
256 | The first page might be a page with regular key/data pairs | |
257 | in which case we have a regular overflow condition and just | |
258 | need to go on to the next page or it might be a big key/data | |
259 | pair in which case we need to fix the big key/data pair. | |
6d1be33f KB |
260 | */ |
261 | static int | |
262 | ugly_split( obucket, old_bufp, new_bufp, copyto, moved ) | |
263 | int obucket; /* Same as __split_page */ | |
264 | BUFHEAD *old_bufp; | |
265 | BUFHEAD *new_bufp; | |
266 | u_short copyto; /* First byte on page which contains key/data values */ | |
267 | int moved; /* number of pairs moved to new page */ | |
268 | { | |
269 | register BUFHEAD *bufp = old_bufp; /* Buffer header for ino */ | |
270 | register u_short *ino = (u_short *)old_bufp->page; | |
271 | /* Page keys come off of */ | |
272 | register u_short *np = (u_short *)new_bufp->page; /* New page */ | |
273 | register u_short *op = (u_short *)old_bufp->page; | |
274 | /* Page keys go on to if they | |
275 | aren't moving */ | |
276 | ||
277 | char *cino; /* Character value of ino */ | |
278 | BUFHEAD *last_bfp = NULL; /* Last buffer header OVFL which | |
279 | needs to be freed */ | |
280 | u_short ov_addr, last_addr = 0; | |
281 | u_short n; | |
282 | u_short off; | |
283 | ||
284 | DBT key, val; | |
285 | SPLIT_RETURN ret; | |
286 | ||
287 | n = ino[0]-1; | |
288 | while ( n < ino[0] ) { | |
9316dbf3 KB |
289 | if ( ino[2] < REAL_KEY && ino[2] != OVFLPAGE ) { |
290 | if (__big_split (old_bufp, new_bufp, bufp, ov_addr, obucket, &ret)) { | |
291 | return(-1); | |
292 | } | |
293 | old_bufp = ret.oldp; | |
294 | if ( !old_bufp ) return(-1); | |
295 | op = (u_short *)old_bufp->page; | |
296 | new_bufp = ret.newp; | |
297 | if ( !new_bufp ) return(-1); | |
298 | np = (u_short *)new_bufp->page; | |
299 | bufp = ret.nextp; | |
300 | if ( !bufp ) return(0); | |
301 | cino = (char *)bufp->page; | |
302 | ino = (u_short *)cino; | |
303 | last_bfp = ret.nextp; | |
304 | } else if ( ino[n+1] == OVFLPAGE ) { | |
6d1be33f KB |
305 | ov_addr = ino[n]; |
306 | /* | |
307 | Fix up the old page -- the extra 2 are the fields which | |
308 | contained the overflow information | |
309 | */ | |
310 | ino[0] -= (moved + 2); | |
311 | FREESPACE(ino) = copyto - sizeof(u_short) * (ino[0]+3); | |
312 | OFFSET(ino) = copyto; | |
313 | ||
314 | bufp = __get_buf ( ov_addr, bufp, 0 ); | |
315 | if ( !bufp ) return(-1); | |
316 | ||
317 | ino = (u_short *)bufp->page; | |
318 | n = 1; | |
319 | copyto = hashp->BSIZE; | |
320 | moved = 0; | |
321 | ||
322 | if ( last_bfp ) { | |
323 | __free_ovflpage( last_bfp); | |
324 | } | |
325 | last_bfp = bufp; | |
326 | } | |
6d1be33f KB |
327 | |
328 | ||
a51caf1c | 329 | /* Move regular sized pairs of there are any */ |
6d1be33f KB |
330 | off = hashp->BSIZE; |
331 | for ( n = 1; (n < ino[0]) && (ino[n+1] >= REAL_KEY); n += 2 ) { | |
332 | cino = (char *)ino; | |
c6ad6315 | 333 | key.data = (u_char *)cino + ino[n]; |
6d1be33f | 334 | key.size = off - ino[n]; |
c6ad6315 | 335 | val.data = (u_char *)cino + ino[n+1]; |
6d1be33f KB |
336 | val.size = ino[n] - ino[n+1]; |
337 | off = ino[n+1]; | |
338 | ||
339 | if ( __call_hash ( key.data, key.size ) == obucket ) { | |
340 | /* Keep on old page */ | |
341 | if (PAIRFITS(op,(&key),(&val))) putpair((char *)op, &key, &val); | |
342 | else { | |
343 | old_bufp = __add_ovflpage ( old_bufp ); | |
344 | if ( !old_bufp ) return(-1); | |
345 | op = (u_short *)old_bufp->page; | |
346 | putpair ((char *)op, &key, &val); | |
347 | } | |
348 | old_bufp->flags |= BUF_MOD; | |
349 | } else { | |
350 | /* Move to new page */ | |
351 | if (PAIRFITS(np,(&key),(&val))) putpair((char *)np, &key, &val); | |
352 | else { | |
353 | new_bufp = __add_ovflpage ( new_bufp ); | |
354 | if ( !new_bufp )return(-1); | |
355 | np = (u_short *)new_bufp->page; | |
356 | putpair ((char *)np, &key, &val); | |
357 | } | |
358 | new_bufp->flags |= BUF_MOD; | |
359 | } | |
360 | } | |
361 | } | |
362 | if ( last_bfp ) { | |
363 | __free_ovflpage(last_bfp); | |
364 | } | |
365 | ||
366 | return (0); | |
367 | } | |
368 | /* | |
369 | Add the given pair to the page | |
370 | 1 ==> failure | |
371 | 0 ==> OK | |
372 | */ | |
373 | extern int | |
374 | __addel(bufp, key, val) | |
375 | BUFHEAD *bufp; | |
376 | DBT *key; | |
377 | DBT *val; | |
378 | { | |
379 | register u_short *bp = (u_short *)bufp->page; | |
380 | register u_short *sop; | |
381 | int do_expand; | |
382 | ||
383 | do_expand = 0; | |
384 | while ( bp[0] && (bp[bp[0]] < REAL_KEY) ) { | |
385 | /* Exception case */ | |
386 | if ( bp[2] < REAL_KEY ) { | |
387 | /* This is a big-keydata pair */ | |
388 | bufp = __add_ovflpage(bufp); | |
389 | if ( !bufp ) { | |
390 | return(-1); | |
391 | } | |
392 | bp = (u_short *)bufp->page; | |
393 | } else { | |
394 | /* Try to squeeze key on this page */ | |
395 | if ( FREESPACE(bp) > PAIRSIZE(key,val) ) { | |
396 | squeeze_key ( bp, key, val ); | |
397 | return(0); | |
398 | } else { | |
399 | bufp = __get_buf ( bp[bp[0]-1], bufp, 0 ); | |
400 | if (!bufp) { | |
401 | return(-1); | |
402 | } | |
403 | bp = (u_short *)bufp->page; | |
404 | } | |
405 | } | |
406 | } | |
407 | ||
408 | if ( PAIRFITS(bp,key,val) ) putpair (bufp->page, key, val); | |
409 | else { | |
410 | do_expand = 1; | |
411 | bufp = __add_ovflpage ( bufp ); | |
412 | if (!bufp)return(-1); | |
413 | sop = (u_short *) bufp->page; | |
414 | ||
415 | if ( PAIRFITS(sop, key, val) ) putpair ( (char *)sop, key, val ); | |
416 | else if ( __big_insert ( bufp, key, val ) ) { | |
417 | return(-1); | |
418 | } | |
419 | } | |
420 | bufp->flags |= BUF_MOD; | |
421 | /* | |
422 | If the average number of keys per bucket exceeds the fill factor, | |
423 | expand the table | |
424 | */ | |
425 | hashp->NKEYS++; | |
426 | if (do_expand || | |
427 | (hashp->NKEYS / (hashp->MAX_BUCKET+1) > hashp->FFACTOR) ) { | |
428 | return(__expand_table()); | |
429 | } | |
430 | return(0); | |
431 | } | |
432 | ||
433 | /* | |
434 | returns a pointer, NULL on error | |
435 | */ | |
436 | extern BUFHEAD * | |
437 | __add_ovflpage ( bufp ) | |
438 | BUFHEAD *bufp; | |
439 | { | |
440 | register u_short *sp = (u_short *)bufp->page; | |
441 | ||
442 | u_short ovfl_num; | |
443 | u_short ndx, newoff; | |
444 | char *op; | |
445 | DBT okey, oval; | |
446 | #ifdef DEBUG1 | |
447 | int tmp1, tmp2; | |
448 | #endif | |
449 | ||
450 | bufp->flags |= BUF_MOD; | |
451 | ovfl_num = overflow_page (); | |
452 | #ifdef DEBUG1 | |
453 | tmp1 = bufp->addr; | |
454 | tmp2 = bufp->ovfl?bufp->ovfl->addr:0; | |
455 | #endif | |
456 | if (!ovfl_num || !(bufp->ovfl = __get_buf ( ovfl_num, bufp, 1 ))) { | |
457 | return(NULL); | |
458 | } | |
459 | bufp->ovfl->flags |= BUF_MOD; | |
460 | #ifdef DEBUG1 | |
461 | fprintf ( stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n", tmp1, tmp2, | |
462 | bufp->ovfl->addr ); | |
463 | #endif | |
464 | ndx = sp[0]; | |
465 | /* | |
466 | Since a pair is allocated on a page only if there's room | |
467 | to add an overflow page, we know that the OVFL information | |
468 | will fit on the page | |
469 | */ | |
470 | sp[ndx+4] = OFFSET(sp); | |
471 | sp[ndx+3] = FREESPACE(sp) - OVFLSIZE; | |
472 | sp[ndx+1] = ovfl_num; | |
473 | sp[ndx+2] = OVFLPAGE; | |
474 | sp[0] = ndx+2; | |
475 | #ifdef HASH_STATISTICS | |
476 | hash_overflows++; | |
477 | #endif | |
478 | return(bufp->ovfl); | |
479 | } | |
480 | ||
481 | /* | |
482 | 0 indicates SUCCESS | |
483 | -1 indicates FAILURE | |
484 | */ | |
485 | extern int | |
486 | __get_page ( p, bucket, is_bucket, is_disk, is_bitmap ) | |
487 | char *p; | |
488 | int bucket; | |
489 | int is_bucket; | |
490 | int is_disk; | |
491 | int is_bitmap; | |
492 | { | |
493 | register int size; | |
494 | register int fd; | |
495 | register int page; | |
496 | u_short *bp; | |
497 | int rsize; | |
498 | ||
499 | fd = hashp->fp; | |
500 | size = hashp->BSIZE; | |
501 | ||
9316dbf3 | 502 | if ( (fd == -1) || !is_disk ) { |
6d1be33f KB |
503 | PAGE_INIT(p); |
504 | return(0); | |
505 | } | |
506 | ||
507 | if ( is_bucket) page = BUCKET_TO_PAGE (bucket); | |
508 | else page = OADDR_TO_PAGE (bucket); | |
867ff150 | 509 | if ((lseek ( fd, page << hashp->BSHIFT, SEEK_SET ) == -1) || |
6d1be33f KB |
510 | ((rsize = read ( fd, p, size )) == -1 )) { |
511 | return(-1); | |
512 | } | |
513 | bp = (u_short *)p; | |
514 | if ( !rsize ) { | |
515 | bp[0] = 0; /* We hit the EOF, so initialize a new page */ | |
516 | } else if ( rsize != size ) { | |
517 | errno = EFTYPE; | |
518 | return(-1); | |
519 | } | |
520 | if (!bp[0]) { | |
521 | PAGE_INIT(p); | |
522 | } else if ( hashp->LORDER != BYTE_ORDER ) { | |
523 | register int i; | |
524 | register int max; | |
525 | ||
526 | if ( is_bitmap ) { | |
527 | max = hashp->BSIZE >> 2; /* divide by 4 */ | |
528 | for ( i=0; i < max; i++ ) { | |
529 | BLSWAP(((long *)p)[i]); | |
530 | } | |
531 | } else { | |
532 | BSSWAP(bp[0]); | |
533 | max = bp[0] + 2; | |
534 | for ( i=1; i <= max; i++ ) { | |
535 | BSSWAP(bp[i]); | |
536 | } | |
537 | } | |
538 | } | |
539 | return (0); | |
540 | } | |
541 | ||
542 | /* | |
543 | Write page p to disk | |
544 | -1==>failure | |
545 | 0==> OK | |
546 | */ | |
547 | extern int | |
548 | __put_page ( p, bucket, is_bucket, is_bitmap ) | |
549 | char *p; | |
550 | int bucket; | |
551 | int is_bucket; | |
552 | int is_bitmap; | |
553 | { | |
554 | register int size; | |
555 | register int fd; | |
556 | register int page; | |
557 | int wsize; | |
558 | ||
559 | size = hashp->BSIZE; | |
a51caf1c | 560 | if ( (hashp->fp == -1) && open_temp() ) return (1); |
6d1be33f KB |
561 | fd = hashp->fp; |
562 | ||
563 | if ( hashp->LORDER != BYTE_ORDER ) { | |
564 | register int i; | |
565 | register int max; | |
566 | ||
567 | if ( is_bitmap ) { | |
568 | max = hashp->BSIZE >> 2; /* divide by 4 */ | |
569 | for ( i=0; i < max; i++ ) { | |
570 | BLSWAP(((long *)p)[i]); | |
571 | } | |
572 | } else { | |
573 | max = ((u_short *)p)[0] + 2; | |
574 | for ( i=0; i <= max; i++ ) { | |
575 | BSSWAP(((u_short *)p)[i]); | |
576 | } | |
577 | } | |
578 | } | |
579 | if (is_bucket ) page = BUCKET_TO_PAGE (bucket); | |
580 | else page = OADDR_TO_PAGE ( bucket ); | |
867ff150 | 581 | if ((lseek ( fd, page << hashp->BSHIFT, SEEK_SET ) == -1) || |
6d1be33f KB |
582 | ((wsize = write ( fd, p, size )) == -1 )) { |
583 | /* Errno is set */ | |
584 | return(-1); | |
585 | } | |
586 | if ( wsize != size ) { | |
587 | errno = EFTYPE; | |
588 | return(-1); | |
589 | } | |
590 | return(0); | |
591 | } | |
592 | #define BYTE_MASK ((1 << INT_BYTE_SHIFT) -1) | |
593 | /* | |
594 | Initialize a new bitmap page. Bitmap pages are left in memory | |
595 | once they are read in. | |
596 | */ | |
597 | extern u_long * | |
598 | __init_bitmap(pnum, nbits, ndx) | |
599 | u_short pnum; | |
600 | int nbits; | |
601 | int ndx; | |
602 | { | |
603 | u_long *ip; | |
604 | int clearints; | |
605 | int clearbytes; | |
606 | ||
607 | if ( !(ip = (u_long *)malloc (hashp->BSIZE)) ) return (NULL); | |
ce17e0e0 | 608 | hashp->exmaps++; |
6d1be33f KB |
609 | clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1; |
610 | clearbytes = clearints << INT_TO_BYTE; | |
611 | memset ((char *)ip, 0, clearbytes ); | |
612 | memset ( ((char *) ip) + clearbytes, 0xFF, | |
613 | hashp->BSIZE-clearbytes ); | |
614 | ip[clearints-1] = ALL_SET << (nbits & BYTE_MASK); | |
615 | SETBIT(ip, 0); | |
616 | hashp->BITMAPS[ndx] = pnum; | |
617 | hashp->mapp[ndx] = ip; | |
618 | return(ip); | |
619 | } | |
620 | static int | |
621 | first_free ( map ) | |
622 | u_long map; | |
623 | { | |
624 | register u_long mask; | |
625 | register u_long i; | |
626 | ||
627 | mask = 0x1; | |
628 | for ( i=0; i < BITS_PER_MAP; i++ ) { | |
629 | if ( !(mask & map) ) return(i); | |
630 | mask = mask << 1; | |
631 | } | |
632 | return ( i ); | |
633 | } | |
634 | ||
635 | static u_short | |
636 | overflow_page ( ) | |
637 | { | |
638 | register int max_free; | |
639 | register int splitnum; | |
640 | register u_long *freep; | |
641 | register int offset; | |
642 | u_short addr; | |
643 | int in_use_bits; | |
644 | int free_page, free_bit; | |
645 | int i, j, bit; | |
646 | #ifdef DEBUG2 | |
647 | int tmp1, tmp2; | |
648 | #endif | |
649 | ||
650 | splitnum = __log2(hashp->MAX_BUCKET); | |
651 | max_free = hashp->SPARES[splitnum]; | |
652 | ||
653 | free_page = (max_free-1) >> (hashp->BSHIFT + BYTE_SHIFT); | |
654 | free_bit = (max_free-1) & ((hashp->BSIZE << BYTE_SHIFT) - 1); | |
655 | ||
656 | /* Look through all the free maps to find the first free block */ | |
657 | for ( i = 0; i <= free_page; i++ ) { | |
658 | if (!(freep = (u_long *)hashp->mapp[i]) ) return(NULL); | |
659 | if ( i == free_page ) in_use_bits = free_bit; | |
660 | else in_use_bits = (hashp->BSIZE << BYTE_SHIFT) -1; | |
661 | ||
662 | for (j = 0, bit = 0; bit <= in_use_bits; j++, bit += BITS_PER_MAP ) { | |
663 | if ( freep[j] != ALL_SET ) goto found; | |
664 | } | |
665 | } | |
666 | /* No Free Page Found */ | |
667 | hashp->SPARES[splitnum]++; | |
668 | offset = hashp->SPARES[splitnum] - | |
669 | (splitnum ? hashp->SPARES[splitnum-1] : 0); | |
670 | ||
671 | /* Check if we need to allocate a new bitmap page */ | |
672 | if ( free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1 ) { | |
673 | free_page++; | |
674 | if ( free_page >= NCACHED ) { | |
675 | fprintf ( stderr, | |
676 | "HASH: Out of overflow pages. Increase page size\n" ); | |
677 | return(NULL); | |
678 | } | |
679 | /* | |
680 | This is tricky. The 1 indicates that you want the | |
681 | new page allocated with 1 clear bit. Actually, you | |
682 | are going to allocate 2 pages from this map. The first | |
683 | is going to be the map page, the second is the overflow | |
684 | page we were looking for. The init_bitmap routine | |
685 | automatically, sets the first bit of itself to indicate | |
686 | that the bitmap itself is in use. We would explicitly | |
687 | set the second bit, but don't have to if we tell init_bitmap | |
688 | not to leave it clear in the first place. | |
689 | */ | |
690 | __init_bitmap ( OADDR_OF(splitnum, offset), 1, free_page ); | |
691 | hashp->SPARES[splitnum]++; | |
692 | #ifdef DEBUG2 | |
693 | free_bit = 2; | |
694 | #endif | |
695 | offset++; | |
696 | } else { | |
697 | /* | |
698 | Free_bit addresses the last used bit. Bump it to | |
699 | address the first available bit. | |
700 | */ | |
701 | free_bit++; | |
702 | SETBIT ( freep, free_bit ); | |
703 | } | |
704 | ||
705 | /* Calculate address of the new overflow page */ | |
706 | if ( offset > SPLITMASK ) { | |
707 | fprintf ( stderr, | |
708 | "HASH: Out of overflow pages. Increase page size\n" ); | |
709 | return(NULL); | |
710 | } | |
711 | addr = OADDR_OF(splitnum, offset); | |
712 | #ifdef DEBUG2 | |
713 | fprintf ( stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", | |
714 | addr, free_bit, free_page ); | |
715 | #endif | |
716 | return(addr); | |
717 | ||
718 | found: | |
719 | bit = bit + first_free(freep[j]); | |
720 | SETBIT(freep,bit); | |
721 | #ifdef DEBUG2 | |
722 | tmp1 = bit; | |
723 | tmp2 = i; | |
724 | #endif | |
725 | /* | |
726 | Bits are addressed starting with 0, but overflow pages are | |
727 | addressed beginning at 1. Bit is a bit addressnumber, so we | |
728 | need to increment it to convert it to a page number. | |
729 | */ | |
730 | bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT)); | |
731 | ||
732 | /* Calculate the split number for this page */ | |
733 | for ( i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++ ); | |
734 | offset =(i ? bit - hashp->SPARES[i-1] : bit ); | |
735 | if ( offset >= SPLITMASK ) return(NULL);/* Out of overflow pages */ | |
736 | addr = OADDR_OF(i, offset); | |
737 | #ifdef DEBUG2 | |
738 | fprintf ( stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", | |
739 | addr, tmp1, tmp2 ); | |
740 | #endif | |
741 | ||
742 | /* Allocate and return the overflow page */ | |
743 | return (addr); | |
744 | } | |
745 | ||
746 | /* | |
747 | Mark this overflow page as free. | |
748 | */ | |
749 | __free_ovflpage ( obufp ) | |
750 | BUFHEAD *obufp; | |
751 | { | |
752 | register u_short addr = obufp->addr; | |
753 | int free_page, free_bit; | |
754 | int bit_address; | |
755 | u_short ndx; | |
756 | u_long *freep; | |
757 | int j; | |
758 | ||
759 | #ifdef DEBUG1 | |
760 | fprintf ( stderr, "Freeing %d\n", addr ); | |
761 | #endif | |
762 | ndx = (((u_short)addr) >> SPLITSHIFT); | |
763 | bit_address = (ndx ? hashp->SPARES[ndx-1] : 0) + (addr & SPLITMASK) - 1; | |
764 | free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT)); | |
765 | free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1); | |
766 | ||
767 | freep = hashp->mapp[free_page]; | |
768 | assert(freep); | |
769 | CLRBIT(freep, free_bit); | |
770 | #ifdef DEBUG2 | |
771 | fprintf ( stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n", | |
772 | obufp->addr, free_bit, free_page ); | |
773 | #endif | |
774 | __reclaim_buf ( obufp ); | |
775 | return; | |
776 | } | |
777 | ||
778 | /* | |
779 | 0 success | |
780 | -1 failure | |
781 | */ | |
782 | static int | |
783 | open_temp() | |
784 | { | |
2c4a3a07 | 785 | sigset_t set, oset; |
b628fad1 | 786 | static char namestr[] = "_hashXXXXXX"; |
2c4a3a07 KB |
787 | |
788 | /* Block signals; make sure file goes away at process exit. */ | |
789 | sigemptyset(&set); | |
790 | sigaddset(&set, SIGHUP); | |
791 | sigaddset(&set, SIGINT); | |
792 | sigaddset(&set, SIGQUIT); | |
793 | sigaddset(&set, SIGTERM); | |
794 | (void)sigprocmask(SIG_BLOCK, &set, &oset); | |
795 | if ((hashp->fp = mkstemp ( namestr )) != -1) { | |
796 | (void)unlink(namestr); | |
797 | (void)fcntl(hashp->fp, F_SETFD, 1); | |
6d1be33f | 798 | } |
2c4a3a07 KB |
799 | (void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL); |
800 | return(hashp->fp != -1 ? 0 : -1); | |
6d1be33f KB |
801 | } |
802 | ||
803 | /* | |
804 | We have to know that the key will fit, but the | |
805 | last entry on the page is an overflow pair, so we | |
806 | need to shift things. | |
807 | */ | |
808 | static void | |
809 | squeeze_key ( sp, key, val ) | |
810 | u_short *sp; | |
811 | DBT *key; | |
812 | DBT *val; | |
813 | { | |
814 | register char *p = (char *)sp; | |
815 | u_short free_space, off; | |
816 | u_short pageno, n; | |
817 | ||
818 | n = sp[0]; | |
819 | free_space = FREESPACE(sp); | |
820 | off = OFFSET(sp); | |
821 | ||
822 | pageno = sp[n-1]; | |
823 | off -= key->size; | |
824 | sp[n-1] = off; | |
825 | bcopy ( key->data, p + off, key->size ); | |
826 | off -= val->size; | |
827 | sp[n] = off; | |
828 | bcopy ( val->data, p + off, val->size ); | |
829 | sp[0] = n+2; | |
830 | sp[n+1] = pageno; | |
831 | sp[n+2] = OVFLPAGE; | |
832 | FREESPACE(sp) = free_space - PAIRSIZE(key,val); | |
833 | OFFSET(sp) = off; | |
834 | } | |
835 | ||
836 | #ifdef DEBUG4 | |
837 | print_chain ( addr ) | |
838 | short addr; | |
839 | { | |
840 | BUFHEAD *bufp; | |
841 | short *bp; | |
842 | short oaddr; | |
843 | ||
844 | fprintf ( stderr, "%d ", addr ); | |
845 | bufp = __get_buf ( (int)addr, NULL, 0 ); | |
846 | bp = (short *)bufp->page; | |
847 | while ( bp[0] && | |
848 | ((bp[bp[0]] == OVFLPAGE) || | |
849 | ((bp[0] > 2) && bp[2] < REAL_KEY))) { | |
850 | oaddr = bp[bp[0]-1]; | |
851 | fprintf ( stderr, "%d ", (int)oaddr ); | |
852 | bufp = __get_buf ( (int)oaddr, bufp, 0 ); | |
853 | bp = (short *)bufp->page; | |
854 | } | |
855 | fprintf ( stderr, "\n" ); | |
856 | } | |
857 | #endif |